System, method, and apparatus for leaching cast components

Abstract

A method includes removing a casting shell and core from a cast component, which may be a gas turbine blade. The method further includes utilizing a focused removal technique, such as a water jet or laser drill, to remove a portion of a virtual pattern cast (VPC) shell from the cast component. The cast component is then exposed to a leaching solution and high pressure water wash to remove an internal core material and a portion of the VPC shell remainder from the cast component. The method further includes exposing the cast component to a high agitation leaching solution and to the high pressure water wash for a minimal time. An electroless nickel-boron coating is then applied to the cast component, and an electrolytic palladium coating is further applied to the cast component. The cast component is further exposed to a high agitation leaching solution for an extended period.

What is claimed is: 
     
       1. A method, comprising:
 utilizing a focused removal technique to remove at least a portion of a virtual pattern cast (VPC) shell from a cast component; 
 exposing the cast component to a leaching solution and a first high pressure water wash to remove an internal core material from the cast component and to remove at least a portion of a VPC shell remainder; 
 operating the first high pressure water wash with the cast component exposed to the leaching solution; 
 exposing the cast component to a first high agitation leaching solution, the first high agitation leaching solution comprising a leaching solution subject to intermittent boiling caused by at least one of heating the first high agitation leaching solution and reducing a pressure in a submersion vessel; 
 applying an electroless nickel-boron coating to the cast component; 
 applying an electrolytic palladium coating to the cast component; and 
 exposing the cast component to a second high agitation leaching solution to remove an internal core material remainder, 
 wherein the step of exposing the cast component to the second high agitation leaching solution follows the steps of applying an electroless nickel-boron coating and applying an electrolytic palladium coating. 
 
     
     
       2. The method of  claim 1 , wherein the focused removal technique comprises at least one of a water jet and a laser drill. 
     
     
       3. The method of  claim 1 , wherein the electroless nickel-boron coating comprises a thickness of between about 0.0002 and 0.0003 inches. 
     
     
       4. The method of  claim 1 , wherein the electrolytic palladium coating comprises a thickness of between about 0.0002 and 0.0003 inches. 
     
     
       5. The method of  claim 1 , peening the cast component with glass beads before exposing the cast component to the second high agitation leaching solution. 
     
     
       6. The method of  claim 1 , wherein exposing the cast component to the second high agitation leaching solution comprises exposing the cast component to the high agitation leaching solution for approximately three days. 
     
     
       7. The method of  claim 1 , wherein the cast component comprises a superalloy, and wherein the VPC shell and internal core material comprise a ceramic. 
     
     
       8. The method of  claim 1 , wherein the cast component comprises a casting of a gas turbine engine blade. 
     
     
       9. The method of  claim 1 , further comprising exposing the cast component to a second high pressure water wash while exposing the cast component to the first high agitation leaching solution. 
     
     
       10. The method of  claim 9 , further comprising exposing the cast component to the first high agitation leaching solution for a time over which 50% of the remaining casting shell and a core material is removed. 
     
     
       11. The method of  claim 1 , wherein the leaching solution comprises a low concentration KOH solution. 
     
     
       12. The method of  claim 11 , wherein the low concentration KOH solution comprises a solution of less than 65% KOH by weight. 
     
     
       13. A method, comprising:
 utilizing least one of a water jet removal and a laser drilling removal to remove at least a portion of a virtual pattern cast (VPC) shell from a cast component; 
 exposing the cast component to a KOH bath and a high pressure water wash to remove an internal core material from the cast component and at least a portion of a VPC shell remainder; 
 operating the first high pressure water wash with the cast component exposed to the KOH solution; 
 exposing the cast component to a high agitation KOH solution and the high pressure water wash, the high agitation KOH solution comprising a KOH solution subject to intermittent boiling caused by at least one of heating the KOH solution and reducing a pressure in a submersion vessel; 
 applying an electroless nickel-boron coating to the cast component; 
 applying an electrolytic palladium coating to the cast component; and 
 exposing the cast component to the high agitation KOH solution to remove an internal core material remainder, 
 wherein the step of exposing the cast component to the high agitation KOH solution follows the steps of applying an electroless nickel-boron coating and applying an electrolytic palladium coating. 
 
     
     
       14. The method of  claim 13 , further comprising peening the cast component with glass beads. 
     
     
       15. The method of  claim 14 , wherein the cast component comprises a superalloy, and wherein the VPC shell and internal core material comprise a ceramic. 
     
     
       16. The method of  claim 15 , wherein the cast component comprises a casting of a gas turbine engine blade. 
     
     
       17. The method of  claim 16 , wherein the electroless nickel-boron coating comprises a thickness of between about 0.0002 and 0.0003 inches. 
     
     
       18. The method of  claim 17 , wherein the electrolytic palladium coating comprises a thickness of between about 0.0002 and 0.0003 inches.